According to Andy Rahn, an engineer on the Lightroom team, there is no bias toward which browser is invoked from Lightroom, we simply look to the operating system registry for what the user has defined as the default browser. That’s not to say this always works correctly. There may be issues with certain browsers registering with the operating system correctly as the default browser.

In a follow up with the individual who originally reported the problem on Twitter, it sounded like the issue may be specific to Google Chrome and the Vista 64-bit operating system. Google released an update yesterday that includes changes that include: “Fixed several problems with making Google Chrome the default browser on Windows Vista.”